Logistic regression was conducted to assess whether the demographic variables and the water quality perceptions significantly predicted the use of bottled water for drinking purposes. The assumptions of independence of observations and the linearity of independent variables with the log of the dependent variable were met. When considered together, the ten variables predict whether a respondent uses bottled water (χ2 = 123.55, df = 10, p < 0.001). Table 2 presents the odds ratios that suggest that the odds of drinking bottled water significantly decrease as education, organoleptic perceptions, and environmental concern scores increase. Specifically, the odds of drinking bottled water deteriorate by 0.78 per unit increase of education, by 0.46 per unit increase of organoleptic perceptions, and by 0.76 per unit increase of environmental concern. In contrast, as the score of perceived health risks increases by one unit, the odds of drinking bottled water significantly increase by 1.36. Interestingly, gender, age, income, area satisfaction, perceived surface water quality, and clean water for recreation did not prove significant in modifying the odds of drinking bottled water. The Nagelkerke pseudo R2 indicates a moderate strength of the model in predicting the use of bottled water by respondents (see Table 2). The Hosmer and Lemeshow test of good fit is non-significant, indicating a good model fit (χ2 = 5.89, df = 8, p = 0.659).

Table 2

Summary of logistic regression analysis predicting drinking bottled water (N = 555)

PredictorBSER95% CIWald statisticp
Female 0.08 0.21 1.09 [0.72, 1.66] 0.17 0.678
Age −0.01 0.01 0.99 [0.97, 1.00] 3.28 0.070
Income −0.01 0.07 0.99 [0.86, 1.15] 0.01 0.917
Education −0.25 0.08 0.78 [0.67, 0.91] 10.16 0.001
Perceived health risks 0.31 0.15 1.36 [1.01, 1.85] 3.99 0.046
Organoleptic perceptions −0.77 0.14 0.46 [0.35, 0.61] 28.89 <0.001
Environmental concern −0.27 0.13 0.76 [0.59, 0.98] 4.46 0.035
Area satisfaction −0.08 0.12 0.93 [0.73, 1.17] 0.40 0.525
Perceived surface water quality 0.04 0.14 1.04 [0.79, 1.38] 0.08 0.773
Clean water for recreation 0.49 0.25 1.64 [0.99, 2.69] 3.79 0.051
Pseudo R2 (Nagelkerke) 0.274
PredictorBSER95% CIWald statisticp
Female 0.08 0.21 1.09 [0.72, 1.66] 0.17 0.678
Age −0.01 0.01 0.99 [0.97, 1.00] 3.28 0.070
Income −0.01 0.07 0.99 [0.86, 1.15] 0.01 0.917
Education −0.25 0.08 0.78 [0.67, 0.91] 10.16 0.001
Perceived health risks 0.31 0.15 1.36 [1.01, 1.85] 3.99 0.046
Organoleptic perceptions −0.77 0.14 0.46 [0.35, 0.61] 28.89 <0.001
Environmental concern −0.27 0.13 0.76 [0.59, 0.98] 4.46 0.035
Area satisfaction −0.08 0.12 0.93 [0.73, 1.17] 0.40 0.525
Perceived surface water quality 0.04 0.14 1.04 [0.79, 1.38] 0.08 0.773
Clean water for recreation 0.49 0.25 1.64 [0.99, 2.69] 3.79 0.051
Pseudo R2 (Nagelkerke) 0.274

Drinking bottled water coded as 0 = does not use bottled water, 1 = uses bottled water.

SE = standard error for regression coefficient (B).

CI = confidence interval for odds ratio (OR).

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